| Message ID | 20220127015226.QSDavwGEn%akpm@linux-foundation.org |
|---|---|
| State | New |
| Headers | show |
| Series | + mm-debug_vm_pgtable-remove-pte-entry-from-the-page-table.patch added to -mm tree | expand |
--- a/mm/debug_vm_pgtable.c~mm-debug_vm_pgtable-remove-pte-entry-from-the-page-table +++ a/mm/debug_vm_pgtable.c @@ -171,6 +171,8 @@ static void __init pte_advanced_tests(st ptep_test_and_clear_young(args->vma, args->vaddr, args->ptep); pte = ptep_get(args->ptep); WARN_ON(pte_young(pte)); + + ptep_get_and_clear_full(args->mm, args->vaddr, args->ptep, 1); } static void __init pte_savedwrite_tests(struct pgtable_debug_args *args)
The patch titled Subject: mm/debug_vm_pgtable: remove pte entry from the page table has been added to the -mm tree. Its filename is mm-debug_vm_pgtable-remove-pte-entry-from-the-page-table.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-debug_vm_pgtable-remove-pte-entry-from-the-page-table.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-debug_vm_pgtable-remove-pte-entry-from-the-page-table.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Pasha Tatashin <pasha.tatashin@soleen.com> Subject: mm/debug_vm_pgtable: remove pte entry from the page table Patch series "page table check fixes and cleanups", v4. Two fixes: mm/debug_vm_pgtable: remove pte entry from the page table - remove a pte entry from the page table at the end of debug_vm_pgtable pte test mm/khugepaged: unify collapse pmd clear, flush and free mm/page_table_check: check entries at pmd levels - check pmd level in page_table_check for PTE regular entries prior to freeing. repro.c: https://gist.github.com/soleen/fdcd501d5df103976245fe84e9535087 config: https://gist.github.com/soleen/8a56f923c2fea9ce9c75b4e2517d4162 qemu_script: https://gist.github.com/soleen/f4be4795826b7ab1a51ae659582e179c base image: https://storage.googleapis.com/syzkaller/wheezy.img https://storage.googleapis.com/syzkaller/wheezy.img.key Small cleanup: mm/page_table_check: use unsigned long for page counters and cleanup This patch (of 4): The pte entry that is used in pte_advanced_tests() is never removed from the page table at the end of the test. The issue is detected by page_table_check, to repro compile kernel with the following configs: CONFIG_DEBUG_VM_PGTABLE=y CONFIG_PAGE_TABLE_CHECK=y CONFIG_PAGE_TABLE_CHECK_ENFORCED=y During the boot the following BUG is printed: [ 2.262821] debug_vm_pgtable: [debug_vm_pgtable ]: Validating architecture page table helpers [ 2.276826] ------------[ cut here ]------------ [ 2.280426] kernel BUG at mm/page_table_check.c:162! [ 2.284118] invalid opcode: 0000 [#1] PREEMPT SMP PTI [ 2.287787] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.16.0-11413-g2c271fe77d52 #3 [ 2.293226] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014 ... The entry should be properly removed from the page table before the page is released to the free list. Link: https://lkml.kernel.org/r/20220126183637.1840960-2-pasha.tatashin@soleen.com Fixes: a5c3b9ffb0f4 ("mm/debug_vm_pgtable: add tests validating advanced arch page table helpers") Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Tested-by: Zi Yan <ziy@nvidia.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Paul Turner <pjt@google.com> Cc: Wei Xu <weixugc@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Will Deacon <will@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Jiri Slaby <jirislaby@kernel.org> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Hugh Dickins <hughd@google.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: <stable@vger.kernel.org> [5.9+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> --- mm/debug_vm_pgtable.c | 2 ++ 1 file changed, 2 insertions(+)